A Combined Experimental and Theoretical investigation of reactive flow in brittle media with applications to solid Earth geodynamics

在自然界和工程世界中，许多重要的过程都涉及到将流体渗透到材料中，然后这些材料发生反应，形成体积大得多的新材料。这些巨大的体积变化反过来又被认为会导致压裂，这为流体渗透开辟了新的途径，可能会导致一系列被称为反应诱导破裂的过程中的广泛裂解材料。虽然许多自然系统提供了这些过程的间接证据，但人们对这些机制的物理和效率(或者它们是否有效)知之甚少。这一建议的目的是通过结合实验室实验、理论和反应脆性材料的高级计算模型来加深对反应破裂过程的基本理解。对这些过程的更好理解可能会导致有效的碳固存或碳氢化合物提取的新的工程方法，可以洞察诱发地震活动以及自然界中重要的地球科学过程。在这个奖项中，我们将结合简化系统上的实验室岩石力学实验和计算模型，这些计算模型可以直接针对实验来测试和验证一系列流体力学破坏理论。室内实验将在Lamont-S三轴变形仪上进行，控制流体流动，监测应力、孔压、声发射和渗透率变化。实验将研究模拟材料上的水合和脱水反应，这些材料被选为在简化的几何结构中提供大的体积变化。我们将探索嵌套的材料圆柱体的行为，内部有一个反应圆柱体，可以产生或吸收水合流体，周围是在不同围压水平下的脆性岩石的外部圆柱体。建模将是哥伦比亚大学多个系和学校的合作成果，并使用由PI开发的开源计算框架。实验的直接建模将为测试假设、验证理论以及校准本构关系和破坏模型提供所需的控制。然后，改进的流体-脆性固体相互作用的理论模型可以扩展到探索它们对大规模地球动力学的影响，例如通过俯冲带的挥发循环。

Many important processes in the natural and engineered world involve the infiltration of fluids into materials that then react to form new materials with significantly larger volume. These large volume changes, in turn are thought to induce fracturing which opens up new avenues for fluid infiltration, potentially leading to a cascade of pervasively cracked materials in a process dubbed ?reaction induced cracking?. While many natural systems give indirect evidence of these processes, very little is understood about the physics and efficiency of these mechanisms (or if they even work). The purpose of this proposal is to develop a fundamental understanding of the reactive cracking process by combining laboratory experiments, theory and advanced computational models of reactive brittle materials. A better understanding of these processes could lead to new engineering methods for efficient carbon sequestration or hydrocarbon extraction, could give insight into induced seismicity as well important Earth science processes in the natural world.During this award, we will combine laboratory rock mechanics experiments on simplified systems with computational models that can be used to test and validate a range of hydro-mechanical failure theories directly against the experiments. Lab experiments will be conducted in Lamont?s tri-axial deformation apparatus, with control of fluid flow and monitoring of stresses, pore pressures, acoustic emissions and permeability changes. Experiments will investigate both hydration and dehydration reactions on analog materials chosen to provide large volume changes in a simplified geometry. We will explore the behavior of nested cylinders of materials with an interior reactive cylinder that can either produce or ingest hydrous fluids, surrounded by an outer cylinder of brittle rock under various level of confining pressure. The modeling will be a collaborative effort across multiple departments and schools at Columbia and use an open-source computational framework developed by the PIs. Direct modeling of the experiments will provide the needed control for testing hypotheses, validating theories, and calibrating constitutive relations and failure models. Improved theoretical models of fluid-brittle solid interaction can then be extended to explore their consequences for large-scale geodynamics such as volatile cycling through subduction zones.